Handbook of Information Security Management
(Publisher: CRC Press LLC)
Author(s): Hal Tipton and Micki Krause, Consulting Editors
ISBN: 0849399475
Publication Date: 01/01/98

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Boosting Backup

If desktop users are on a network, part of the backup problem has been solved. Any data they store on the file server will be backed up as part of normal network management (any network file server worthy of the name will have a built-in backup device, typically tape, and any network administrator worthy of the name will use it diligently). But unless the network workstations are diskless, there will be a residual problem of local backup. It is possible to backup local workstation storage through the file server, but this is not always practical (typically the workstation must be on with the user logged in but not using the machine, an arrangement that has security implications). Besides, users may be keeping some data locally on removable media, such as diskettes.

What is required is a clear policy on local backup (as well as on the use of removable media). But how do you persuade users to do better in the backup department? Make it easier to do and make people want to do it. Making people want to do something is mainly a question of education. People need to be told why backups are important, and this means more than simply saying, “Because it is company policy.” A positive approach is to educate, using scenarios in which backup saves the day. Users should be made aware of the variety of ways in which data can be lost or damaged. But don’t dwell too long on the negative — emphasize the comfortable feeling that comes from knowing that you have current backups.

Making backup easy to do involves some decisions about hardware and software. What backup media will be used — floppy disks, tape, optical disks, cartridges? What backup software will be used? Will computers attached to a network be backed up independently or by the network? Will macros, batch files, or automated schedule programs be used to simplify the procedures? If so, who is responsible for creating and configuring these? Beyond these are questions such as how often backup should be done, what files should be backed up, and where the backup media will be stored. You should establish explicit guidelines on these matters so that users are clear about what their backup responsibilities are. Such rules and regulations can be incorporated into an education campaign. To summarize, a general improvement in backup habits is likely to occur if you:

  1. Make backup a policy, not an option.
  2. Make backup desirable.
  3. Make backup easy.
  4. Make backup mandatory.
  5. Make sure users comply with backup policy.

Backup Strategy

There is no universal path to quick and easy backup. If there was, everyone would be taking it and cheerfully doing their daily backup. The user with unlimited resources has some excellent options, the most attractive probably being optical disks. But the whole culture of personal computers is shaped by economics and the inescapable fact is that most individuals and organizations do not have unlimited resources. To make effective use of time and money devoted to backup, a backup strategy should be developed. Consider what files need to be backed up, and how often the backup should be performed. Begin by considering the type of backup that is needed.

Image Backup

Early personal computer tape drives could only perform a complete and total backup of every file on the hard disk, referred to as an image backup. This is a “warts and all” image, a track-by-track reading of the surface of the hard disk, including hidden and system files, even unused areas and cross-linked files. This caused problems when restoring data; for example, if the hard drive to which the data were being restored was not exactly the same make and model as the original. Some systems only allowed an image backup to be restored in its entirety, meaning that bad sectors were restored along with the good. But image backup has some advantages, such as speed. By treating the contents of the hard disk as a continuous stream of data bits, a lot of time that would otherwise be spent searching the disk for parts of specific files is saved. Recently, the use of image backup has been revived by more intelligent software that eliminates the shortcomings of early systems.

File-By-File

The alternative to an image backup is a file-by-file backup in which the user selects the directories and files to be backed up. The software then reads and writes each one in turn. While this may take longer than an image backup, it allows quick restoration of a single file or group of files. A file-by-file backup can also be faster than an image backup when only a small percentage of the hard disk has been used, or if the data on the hard disk are “optimized.”14 A file-by-file backup can be complete, including all of the files on the hard disk, but this is different from an image backup. In a file-by-file backup, the files are read individually rather than as a pattern on the disk.

> 14The term “optimized” refers to organizing data on the disk so that files are stored in contiguous sectors, in logical order for the most efficient retrieval. The term “defragmented” is used to describe the process of rearranging files so that they are stored in contiguous sectors.

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